X2goplugin refactoring closes #603
This is a reimplementation of the x2goplugin. There is still a lot of job to do but it's already usable.
This pull request closes #603 , #17 and includes #653 and some GTK improvements.
- Clipboard sync between xephyr and xorg
- work around nxproxy and nxagent instead of using pyhoca/x2goclient
@giox069 If you can I need to test the libsecret part (new gnome-keyring implementation)